I need energy!?

It seems there are not enough hours in the day! I just started grad school, and I am tired all the time. I know I am sleep deprived - I REM as soon as I fall asleep (took a 10 minute nap this morning and dreamt). I've had my blood, and I am not iron deficient. Red Bull doesn't work, and neither does caffeine. On a related note, b/c of an unknown health condition, I'm pretty much restricted to water only (seeing a doc about that this week). But I'm not sure if it's b/c I don't exercise. But when I do, I feel tired, not energized. Should I change my diet? I just started taking Ginseng pills yesterday. I need to stay awake, but I feel really fatigued. Also, I would listen to rock music to stay awake, but that makes it hard to study, and I listen to rock a lot and can fall asleep to it now. Help!